• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.145_146
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• 2009

최근 한국전력의 일선 사업소에서 배전선로 계통운영 업무에 많은 어려움을 겪고 있다. 분산형전원의 보급이 확대되면서 단방향 고장전류로 처리하던 보호협조 및 배전자동화 업무에 문제점이 발생되면서 혼선이 생기고 있는 것이다. 현행 배전선로 보호협조 업무는 모두 방향성이 없는 형태로 OCR, OCGR과 Recloserfh 대변되는 배전용 차단기의 협조방안으로 운영되어 왔으며, 배전자동화의 경우에도 부하측 공장에 대해 고장표시기(Fault Indicator)를 발생시키는 로직을 활용하여 배전선로의 안정화에 크게 기여하여 왔다. 하지만 최근 급속도로 발전하는 신재생에너지 사업과 관련하여 배전선로와 연계된 분산전원이 점차로 많아지고 있으며, 따라서 이제는 양방향 분산전원를 고려한 보호협조가 적용되어야 할 상황이다. 이에 발맞추어 최근 여러각도에서의 분산전원 연계기술에 대한 많은 연구가 진행되고 있다. 본 논문에서는 현행 배전선로에서의 분산전원 연계시 나타나는 문제점과 그 대책에 대해 알아보고자 한다.

• Proceedings of the KIEE Conference
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• 2006.11a
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• pp.369-371
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• 2006

본 논문은 계통 모의시험프로그램을 이용하여 배전계농에서 나타나는 지락 및 단락고장에 대하여 모의시험을 수행하였다. 고장모의시험에서 배전자동화용 개폐기의 고장인지(Fault Indicator)의 동작에 영향을 미치는 고장전류의 변화를 살펴보았다. 그리고, 이러한 고장전류를 감지하여 FI를 배전자동화 시스템 주장치로 보내어주는 FRTU의 정상동작 시험을 위하여 실시간 계통 시뮬레이터를 이용하여 FRTU의 시험방법을 제안하였다.

• Proceedings of the KIEE Conference
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• 1996.07b
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• pp.899-901
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• 1996

KODAS is made up of the Central Control System(CCS) as four Vax workstations linked up with LAN networks, six Substation Communication Control Units(SCCU) installed in substation to transfer data, 125 Feeder Remote Units(FRU) located at the lower position of automated switch to provide the information of Fault Indicator(FI) and three kinds of automated switches to have remote control functions such as SF6 gas feeder automation switch, recloser and gas insulated pad mountes switchgear for under ground line. This paper explains the functions and characteristics in detail about each devices mentioned above.

• Economic and Environmental Geology
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• v.52 no.6
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• pp.573-586
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• 2019

A seismic hazard map based on spatial analysis of various sources of geologic seismic information was developed and assessed for regional seismic vulnerability in South Korea. The indicators for assessment were selected in consideration of the geological characteristics affecting the seismic damage. Probabilistic seismic hazard and fault information were used to be associated with the seismic activity hazard and bedrock depth related with the seismic damage hazard was also included. Each indicator was constructed of spatial information using GIS and geostatistical techniques such as ordinary kriging, line density mapping and simple kriging with local varying means. Three spatial information constructed were integrated by assigning weights according to the research purpose, data resolution and accuracy. In the case of probabilistic seismic hazard and fault line density, since the data uncertainty was relatively high, only the trend was intended to be reflected firstly. Finally, the seismic activity hazard was calculated and then integrated with the bedrock depth distribution as seismic damage hazard indicator. As a result, a seismic hazard map was proposed based on the analysis of three spatial data and the southeast and northwest regions of South Korea were assessed as having high seismic hazard. The results of this study are expected to be used as basic data for constructing seismic risk management systems to minimize earthquake disasters.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.1
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• pp.52-56
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• 2011

The ongoing Superconducting Fault Current Limiter(SFCL) development mainly has focused on the application of commercializaton and power system through combining with normal-conducting device, moving away from current-limiting method, which is solely dependant on the existing superconductor. Compared to the structural development above, on the other hand, the research on applying superconducting current-limiting element to SFCL, the heart of SFCL, still has a lot left to do, apart form traditional resistive type SFCL. In this study, we looked into the current limiting characteristic of SFCL using core and coil. YBCO coated conductor with stainless steel stabilizer layer was verified by the excellent of current-limiting element of the resistive type SFCL that has a high Jc and index as well as being superior in mechanical property. Also, we study temperature characteristics and resistance characteristics, max voltage, response time and current-limiting ability that can be an indicator as current-limiting element while applying to superconducting current-limiting element caused by variation of winding direction, winding ratio of SFCL using core and coil.

• The Journal of the Petrological Society of Korea
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• v.12 no.3
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• pp.101-109
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• 2003

The wavy extinction of quartz can be used as a standard indicator showing the degree of rock deformation. In determine the degree of rock deformation, the intensity of wavy extinction (IWE) of quartz was measured using polarizing microscope, digital camera, and NIH Image program. This method was applied to the granite of Pocheon-Gisanri area, which are divided three type; biotite granite (Gb), garnet biotite granite (Ggb) and two mica granite (Gtm). In this study, measurement of wavy extinction was proceeded Ggb in eastern part and Gb in western part based on the Pocheoneup. The result was that Gb shows low deformation degree below D2, and Ggb represents high deformation degree above D3, generally showing that increasing deformation degree from northwest to southeast in the studied area. It is suggested that the fault which penetrated Ggb in 1/250,000 geological map affected the deformation degree of Ggb.

• The Journal of the Petrological Society of Korea
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• v.11 no.3_4
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• pp.250-258
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• 2002

The wavy extinction of quartz can be used as a standard indicator showing the degree of rock deformation. To determine the degree of rock deformation, the intensity of wavy extinction (IWE) of quartz was measured using petroggraphic microscope, digital camera, and NIH image. In this study, this method was applied to the Cheongsan porphyritic granite, Cheongsan two mica granite, and Baekrok granite to investigate the deformation intensity of Cheongsan area. NIH Image data show a high-grade deformation in the vicinity of the strike-slip fault (between Cheongsan granite and Baekrok granite) and the unconformity (between Cheongsan granite and Youngdong basin). Thus, the main deformation in these areas is most likely to be concentrated on the faults that generate Yeongdong basin and the strike slip faults between Cheongsan granite and Baekrok granite.

• Journal of Electrical Engineering and Technology
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• v.8 no.2
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• pp.354-358
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• 2013

This paper discusses the analysis of arc conductance in a gas circuit breaker (GCB) during current interruption process and the investigation method of the interruption capability. There are some limitations in the application of the computational fluid dynamics (CFD) for the implementation of an arc model around the current zero, despite the fact that it gives good results for the high-current phase arc. In this study, we improved the accuracy in the analysis of the interruption performance by attempting the method using CFD and a mathematical arc model. The arc conductance at 200 ns before current zero (G-200ns) is selected as the indicator to predict the current interruption of the Short Line Fault (SLF). Finally, the proposed method is verified by applying to the actual circuit breakers which have different interruption performances.

• The Journal of the Convergence on Culture Technology
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• v.6 no.4
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• pp.783-788
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• 2020

Surges generated by direct strike or induction of lightning, frequent opening and closing of power system breakers, etc. cause excessive overvoltage, which can interfere with normal operation of transformers, circuit breakers, and power equipment. In order to prevent such phenomena, this study goes further from the method of establishing countermeasures by installing lightning arresters on power equipment or lines in parallel, and furthermore, remotely checking the condition of the lightning arrester and preparing immediate countermeasures when an event occurs. The purpose of the study is to prevent damage in advance.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.10
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• pp.102-111
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• 2021

Maintainability is a major design parameter that includes availability as well as reliability in a RAM (reliability, availability, maintainability) analysis, and is an index that must be considered when developing a system. There is a lack of awareness of the importance of predicting and analyzing maintainability; therefore, it is dependent on past-experience data. To improve the utilization rate, maintainability must be managed as a key indicator to meet the user's requirements for failure maintenance time and to reduce life-cycle costs. To improve the maintainability-prediction accuracy in the detailed design stage, we present a maintainability-prediction method that applies Method B of the Military Standardization Handbook (MIL-HDBK-472) Procedure V, as well as a Korean maintainability-prediction software package that reflects the system complexity.